without more info about what you are actually doing, your preferences and so on nobody can say anything. Your disk cache could be filling, you could have an issue with graphics hardware acceleration or any number of other issues like working with a flaky CoDec or incompatible third-party plug-in.
thanks. more info below... sorry.. first post ever... if more info let me know, and thanks for your help !
it happens with every project, does not matter what plug ins I am using. it starts very good, and then after 5-10 minutes starts to slow down and wont do ram preview anymore, if i purge all does not improve it either.
enable disk cache: on
maximum disck cache size 80GB
folder: I only have one partition. so is in the users/.../library/cache.
---- I have a fusion hard drive so I dont know if that has anything to do with it.
installed Ram 8 GB
ram reserved for other applications 2GB
Reduce cache size when system is lo on memory : on
AE CC 2014 has a few little bugs in it relating to memory, for example: warning “RAM Preview needs 2 or more frames” after scrubbing audio in After Effects CC 2014 (13.0)
If you continue having problems, I'd suggest trying version 12.2.1 of AE. If that works, great! Stick with it until Adobe releases a bug fix update for version 13. If you continue having problems with version 12.2.1, we should continue troubleshooting.